As an example of electronic documents, consider an email system. Email enables users to exchange computer messages via a data network such as the public Internet and the private AOL. The email protocol is a component of the Transport Control Protocol/Internet Protocol (TCP/IP). All online services and Internet Service Providers (ISPs) offer email, and most of them also support gateways for exchanging mail with users of other systems. Email messages typically comprise text, and can have text, graphics, video, sound files, web pages, etc., as attachments to or embedded within the email body.
As another example of electronic documents, consider Web pages. A browser enables the user to access the information available on the World Wide Web. Typically, this information comprises HTML codes that via the browser control how the information, i.e., the Web page, is being displayed for the user.